Effects of memantine and its metabolite Mrz 2/373 on soman-induced inhibition of acetylcholinesterase in vitro.

Memantine is the non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, used in the treatment of Alzheimer's disease. It is also known that memantine pretreatment assured protection of skeletal muscles from poisoning with nerve agents and an interaction between memantine and AChE was proposed. In the study presented we examined interactions of memantine and its main metabolite (1-amino-3-hydroxymethyl-5-methyl adamantine, Mrz 2/373) with AChE in vitro as well as their effect on kinetics of the soman-induced AChE inhibition and aging. The results have shown that memantine and Mrz 2/373 exerted concentration-dependent inhibition of AChE, with Mrz 2/373 being a more potent inhibitor than the parent compound. Addition of soman 7.5 nmol/l induced gradual AChE inhibition that became almost complete after 20 min. Memantine (0.1, 0.5 and 1 mmol/l) and Mrz 2/373 (0.1, 0.5 and 1 mmol/l) concentration-dependently slowed down the AChE inhibition. After 30 min of incubation of AChE with soman, 5 min of aging and 20 min of reactivation by asoxime (HI-6 dichloride), AChE activity was 8.1% in control medium, 30.7% and 41.9% after addition of 1 and 10 mmol/l memantine, and 16.1% after addition of 1 mmol/l Mrz 2/373. It was concluded that it is possible that memantine and Mrz 2/373 can prevent AChE from inhibition by soman, which could, along with known memantine's neuroprotective activity, explain its potent antidotal effect in soman poisoning. The potential effect on aging of the soman-AChE complex warrants further studies.

Sex and Time-of-Day Impact on Anxiety and Passive Avoidance Memory Strategies in Mice.

In humans, anxiety and cognitive processes are age, gender, and time of day dependent. The purpose of the present study was to assess whether the time of day and sex have an influence on anxiety and emotional memory in adult mice. Light-dark and passive avoidance (PA) tests were performed at the beginning and at the end of the light cycle, defined as Zeitgeber time (ZT) ZT0-2.5 and ZT9.5-12, respectively. A baseline difference in anxiety was not found, but on the 24 h retention trial of the PA test, females presented longer latencies to enter into the dark compartment at the ZT0-2.5 time point of the day. The data from the second test day (PA reversal trial) indicated that some animals associated the dark compartment with an aversive stimulus (shock), while others associated the aversive stimulus with crossing from one compartment to another. At the ZT9.5-12, female mice mainly related the aversive stimulus to transferring from one compartment to another, while male mice associated darkness with the aversive stimulus. There was a negative correlation between the frequency of light-dark transitions in the light-dark test and the PA latency on the 24 h retention trial in males tested at ZT0-2.5. The PA latency on the reversal and 24 h retention trials negatively correlated with a risk assessment behavior in male mice tested on ZT0-2.5 and ZT9.5-12, respectively. In conclusion, our data reveal that the impact of motor activity and risk assessment behavior on PA memory formation and applied behavioral strategies are time of day and sex dependent.

Efficacy and Safety of Low-Dose Versus Standard-Dose Alteplase Regimens in Patients with Acute Ischaemic Stroke.

BACKGROUND: The use of intravenous recombinant tissue plasminogen activator, alteplase, at a dose of 0.9 mg/kg is an effective treatment for patients with acute ischaemic stroke; this dose is also associated with high intracerebral haemorrhage rates. The aim of this study was to evaluate whether the low-dose alteplase treatment is as effective and safe as the standard-dose regimen. SUBJECTS AND METHODS: This was a retrospective, single-centre study, and data were collected from the Hospital Stroke Registry. Based on the severity of stroke and the risk of intracerebral haemorrhage, patients were divided into two groups according to the alteplase doses given; the low-dose (0.6 mg/kg) group (n=45) and the standard-dose (0.9 mg/kg) group (n=165). Ninety-day outcomes measured as modified Rankin score and National Institute for Health Stroke Scale (NIHSS) score, as well as symptomatic intracerebral haemorrhage and mortality rates were analysed. RESULTS: The standard-dose group had a slightly more favourable outcome (Rankin score 0-2) at 90 days after alteplase treatment than the low-dose group (64.24% vs. 53.33%), but the difference was not significant. The total intracerebral haemorrhage rate and mortality rate at 90 days were higher in the standard-dose group than in the low-dose group (21.2% vs. 13.3% and 6.1% vs. 0.0%, respectively), but these differences were not statistically significant. CONCLUSION: The low-dose alteplase treatment applied to the patients with high intracerebral haemorrhage risk had comparable efficacy and safety profile to the standard-dose regimen.

Prophylactic potential of memantine against soman poisoning in rats.

BACKGROUND: Carbamates physostigmine and pyridostigmine have been used as a pretreatment against poisoning with nerve agents in order to reversibly inhibit and thus protect from irreversible inhibition a portion of acetylcholinesterase (AChE) in brain and respiratory muscles that is crucial for survival. Memantine, an adamantine derivative, has emerged as a promising alternative to carbamates, since it prevented the fasciculations and skeletal muscle necrosis induced by carbamates and organophosphates, including nerve agents. AIM: This experimental study was undertaken in order to investigate and compare the protective and behavioural effects of memantine and standard carbamates physostigmine and pyridostigmine in rats poisoned with soman and treated with atropine, oxime HI-6 and diazepam. Another goal was to elucidate the mechanisms of the antidotal effect of memantine and its potential synergism with standard antidotes against nerve agents. MATERIALS AND METHODS: Male Wistar rats were used throughout the experiments. In dose-finding experiments memantine was administered at dose interval 0-72 mg/kg sc 60 min before sc injection of soman. In time-finding experiments memantine was injected 18 mg/kg sc 0-1440 min before soman. Standard treatment antidotes - atropine 10 mg/kg, HI-6 50 mg/kg and diazepam 2.5 mg/kg - were administered im within 15 s post-exposure. Soman 0.75 LD50 was used to study its inhibitions of neuromuscular transmission on the phrenic nerve-diaphragm preparation in situ and of tissue AChE activity. Behavioural effects of the prophylactic antidotes were investigated by means of the rotarod test. Based on these data therapeutic index and therapeutic width was calculated for all three prophylactic agents. RESULTS: Memantine pretreatment (18 mg/kg sc) produced in rats poisoned with soman significantly better protective ratios (PRs) than the two carbamates - 1.25 when administered alone and 2.3 when combined with atropine pretreatment and 6.33 and 7.23 with atropine/HI-6 and atropine/HI-6/diazepam post-exposure therapy, respectively. The highest PR of 10.11 obtained in Atr/HI-6-treated rats was achieved after pretreatment with memantine 36 mg/kg. This additional protection lasted for 8 h. All three prophylactic regimens antagonised the soman-induced neuromuscular blockade, but the effect of memantine was fastest. Pretreatment with memantine assured higher AChE activity in brain and diaphragm than in unpretreated rats (46% vs 28% and 68% vs. 38%, respectively). All three prophylactic regimens affected the rotarod performance in rats, but the effect of memantine was relatively strongest. Memantine and pyridostigmine had lowest and highest therapeutic index and therapeutic width, respectively. CONCLUSIONS: Although memantine assures better and longer-lasting protection against soman poisoning in rats than the two carbamates, its small therapeutic index and narrow therapeutic width seriously limit its potential as a pretreatment agent. Despite its behavioural effects, memantine seems to be beneficial antidote when administered after soman, along with atropine/HI-6/diazepam therapy. Mechanism of the antidotal effect of memantine against soman poisoning appears to be a combination of AChE-protecting and NMDA receptor-blocking action.

Efficacy of antidotes and their combinations in the treatment of acute carbamate poisoning in rats.

BACKGROUND: Physostigmine and its analogues neostigmine, pyridostigmine and rivastigmine are carbamates nowadays used in many indications, including antidotal effects against antimuscarinic poisonings, reversal of competitive neuromuscular block, myasthenia gravis, Alzheimer's disease and prophylaxis against nerve agent intoxications. Use of these medicinal carbamates, but also of carbamate insecticides, created need for research into the potential and mechanisms of action of several antidotes against carbamate poisonings, including anticholinergics and oximes. AIM: The goal of this experimental study was to ascertain the life-preserving potential of anticholinergics atropine, hexamethonium and d-tubocurarine, oxime HI-6 and their combinations in rats poisoned with physostigmine or pyridostigmine. MATERIALS AND METHODS: Experiments were performed in Wistar rats. Carbamates were injected subcutaneously (sc) and antidotes intramuscularly (im). Median lethal dose (LD50) in animals treated with antidotes were compared to the ones in saline-treated rats and protective ratios (PRs) were calculated. Atropine (5, 10 and 20 mg/kg), hexamethonium (5, 10 and 20 mg/kg), d-tubocurarine (0.005, 0.010 and 0.020 mg/kg) and oxime HI-6 (25, 50 and 100 mg/kg) were used as monotherapies and in dual combinations, where atropine was the obligatory antidote. Biochemical experiments consisted in measuring of the cholinesterase activities in brain, whole blood and diaphragm in rats 5, 15, 30, 60, 120 and 240 min after poisoning with 0.8 LD50 of physostigmine or pyridostigmine. RESULTS: All the tested antidotes assured some degree of protection against the two carbamates. Atropine and hexamethonium produced better protection in physostigmine-poisoned rats, while d-tubocurarine and HI-6 were more efficacious in pyridostigmine-intoxicated animals. Oxime HI-6 50 mg/kg reactivated acetylcholinesterase (AChE) in brain inhibited by physostigmine and in diaphragm inhibited by pyridostigmine. CONCLUSIONS: Mechanism of physostigmine-induced lethal effect is predominantly central and it involves inhibition of brain AChE, while pyridostigmine produces the same effect exclusively outside the central nervous system, by inhibiting AChE in the respiratory muscles. As a consequence, increasing doses of atropine and their combination with hexamethonium assure excellent protection against physostigmine toxicity, while the best protection against pyridostigmine is provided by a strictly peripherally acting antinicotinic d-tubocurarine and bispyridinium oxime HI-6. The oxime acts as antidote against physostigmine and pyridostigmine poisoning by reactivating AChE in the brain and diaphragm, respectively.

The Efficacy of Amifostine against Multiple-Dose Doxorubicin-Induced Toxicity in Rats.

Amifostine is well known cytoprotector which is efficient when administered before a wide range of antineoplastic agents. The aim of our study was to investigate amifostine effects on doxorubicin-induced toxic changes in rats. Amifostine (75 mg/kg ip) was given 30 min before each dose of doxorubicin (cumulatively 20 mg/kg ip, for 28 days). The animals' whole-body, liver, and kidney weight, serum biochemical examination, as well as microscopic examination of bone marrow, peripheral blood, liver, and kidney, were done on day 56 of the study. Hepatic and renal alterations were carefully quantified by semiquantitative grading scales-hepatic and renal damage score, respectively. In amifostine-pretreated rats, the number of peripheral blood leukocytes was significantly higher in comparison to doxorubicin-only treated group, preferentially protecting neutrophils. In the same group of rats, hepatic and renal alterations associated with polymorphonuclear cell infiltrates were significantly less severe than those observed in animals receiving only doxorubicin. Our results showed that amifostine successfully protected rats against multiple-dose doxorubicin-induced toxicity by complex, and still not fully elucidated mechanisms of action.

Bioequivalence study of two formulations of itraconazole 100 mg capsules in healthy volunteers under fed conditions: a randomized, three-period, reference-replicated, crossover study.

BACKGROUND: The aim of the study was to evaluate the bioequivalence of two itraconazole 100 mg capsule formulations. RESEARCH DESIGN AND METHODS: The single-center, open-label, randomized, three-period, three-sequence, reference-replicated, cross-over study included 38 healthy subjects under fed conditions. In each study period (separated by a 14-day washout), a single oral dose of the test (T) or reference (R) product was administered. Blood samples were collected at pre-dose and up to 72.0 h after administration. The calculated pharmacokinetic parameters, based on the plasma concentrations of itraconazole and hydroxy itraconazole, were AUC0-72h, AUC0-∝, Cmax, Tmax, T1/2 and Kel. RESULTS: The 90% CI for the test/reference geometric means ratio for the parent compound, itraconazole, was in the range from 85.29% to 116.07% for AUC0-72h. Since the coefficient of variation (CV) for the reference product was 44.95% for Cmax, the 90% CI for this parameter for itraconazole was 93.49-133.78%, which was within the proposed limits of the EMA for bioequivalence of 72.15-138.59%. During the study, 4 subjects encountered a total of 14 mild adverse events. CONCLUSIONS: The use of the reference-scaling approach with 3-period design (TRR, RTR, and RRT) was an efficient way to demonstrate that two commercially available oral itraconazole formulations met the predetermined bioequivalence criteria.

Disability, Work Absenteeism, Sickness Benefits, and Cancer in Selected European OECD Countries-Forecasts to 2020.

BACKGROUND: Disability either due to illness, aging, or both causes remains an essential contributor shaping European labor markets. Ability of modern day welfare states to compensate an impaired work ability and absenteeism arising from incapacity is very diverse. The aims of this study were to establish and explain intercountry differences among selected European OECD countries and to provide forecasts of future work absenteeism and expenditures on wage replacement benefits. METHODS: Two major public registries, European health for all database and Organization for Economic Co-operation and Development database (OECD Health Data), were coupled to form a joint database on 12 core indicators. These were related to disability, work absenteeism, and sickness benefits in European OECD countries. Time horizon 1989-2013 was observed. Forecasting analysis was done on mean values of all data for each single variable for all observed countries in a single year. Trends were predicted on a selected time horizon based on the mean value, in our case, 7 years up to 2020. For this purpose, ARIMA prediction model was applied, and its significance was assessed using Ljung-Box Q test. RESULTS: Our forecasts based on ARIMA modeling of available data indicate that up to 2020, most European countries will experience downfall of absenteeism from work due to illness. The number of citizens receiving social/disability benefits and the number being compensated due to health-related absence from work will decline. As opposed to these trends, cancer morbidity may become the top ranked disability driver as hospital discharge diagnoses. Concerning development is the anticipated bold growth of hospital discharge frequencies due to cancer across the region. This effectively means that part of these savings on social support expenditure shall effectively be spent to combat strong cancer morbidity as the major driver of disability. CONCLUSION: We have clearly growing work load for the national health systems attributable to the clinical oncology acting as the major disability contributor. This effectively means that large share of these savings on public expenditure shall effectively be spent to combat strong cancer morbidity. On another side, we have all signs of falling societal responsibility toward the citizens suffering from diverse kinds of incapacity or impaired working ability and independence. Citizens suffering from any of these causes are likely to experience progressively less social support and publicly funded care and work support compared to the golden welfare era of previous decades.

In-hospital mortality analysis in patients with proximal femoral fracture operatively treated by hip arthroplasty procedure.

BACKGROUND/AIM: Hip fracture remains the leading cause of death in trauma among elderly population and is a great burden to national health services. In-patient death analysis is important to evaluate risk factors, make appropriate selection and perform adequate treatment of infections for patients to be operated. The aim of this study was to analyze in-hospital mortality in proximal femoral fracture patients operatively treated with hip arthroplasty procedure. METHODS: We followed 622 consecutive patients, and collected data about age, gender, the presence of infection preoperatively and postoperatively, American Society of Anesthesiologists (ASA) score, diabetes mellitus and the type of surgical procedure. Postoperative infections included pneumonia, urinary tract infections, surgical site infections and sepsis. RESULTS: We found a statistically significant influence of preoperative and postoperative infection presence for in-patient mortality with relative risk for lethal outcome of 4.53 (95% CI: 1.44-14.22) for patients with preoperative infection and 7.5 (95% CI: 1.90-29.48) for patients with postoperative infection. We did not confirm a statistically significant influence of age, gender, ASA score, diabetes mellitus or the type of surgical procedure for increased mortality rate. CONCLUSION: Adequate preoperative selection, risk evaluation and adequate treatment of infections are of the key importance for lowering the risk of death in patients operated due to proximal femoral fracture and treated by hip arthroplasty procedures. Special attention is to be paid for the presence of preoperative and postoperative infections in patients operatively treated due to the risk for increased in-hospital mortality.

Protective effects of glucose-6-phosphate dehydrogenase on neurotoxicity of aluminium applied into the CA1 sector of rat hippocampus.

BACKGROUND & OBJECTIVES: Aluminum (Al) toxicity is closely linked to the pathogenesis of Alzheimer's disease (AD). This experimental study was aimed to investigate the active avoidance behaviour of rats after intrahippocampal injection of Al, and biochemical and immunohistochemical changes in three bilateral brain structures namely, forebrain cortex (FBCx), hippocampus and basal forebrain (BF). METHODS: Seven days after intra-hippocampal (CA1 sector) injection of AlCl3 into adult male Wistar rats they were subjected to two-way active avoidance (AA) tests over five consecutive days. Control rats were treated with 0.9% w/v saline. The animals were decapitated on the day 12 post-injection. The activities of acetylcholinesterase (AChE) and glucose-6-phosphate dehydrogenase (G6PDH) were measured in the FBCx, hippocampus and BF. Immunohistochemical staining was performed for transferrin receptors, amyloid ß and tau protein. RESULTS: The activities of both AChE and G6PDH were found to be decreased bilaterally in the FBCx, hippocampus and basal forebrain compared to those of control rats. The number of correct AA responses was reduced by AlCl3 treatment. G6PDH administered prior to AlCl 3 resulted in a reversal of the effects of AlCl3 on both biochemical and behavioural parameters. Strong immunohistochemical staining of transferrin receptors was found bilaterally in the FBCx and the hippocampus in all three study groups. In addition, very strong amyloid ß staining was detected bilaterally in all structures in AlCl3-treated rats but was moderate in G6PDH/AlCl3-treated rats. Strong tau staining was noted bilaterally in AlCl3-treated rats. In contrast, tau staining was only moderate in G6PDH/AlCl3-treated rats. INTERPRETATION & CONCLUSIONS: Our findings indicated that the G6PDH alleviated the signs of behavioural and biochemical effects of AlCl3-treatment suggesting its involvement in the pathogenesis of Al neurotoxicity and its potential therapeutic benefit. The present model could serve as a useful tool in AD investigations.

Influence of the green tea leaf extract on neurotoxicity of aluminium chloride in rats.

Aluminium may have an important role in the aetiology/pathogenesis/precipitation of Alzheimer's disease. Because green tea (Camellia sinensis L.) reportedly has health-promoting effects in the central nervous system, we evaluated the effects of green tea leaf extract (GTLE) on aluminium chloride (AlCl3 ) neurotoxicity in rats. All solutions were injected into the cornu ammonis region 1 hippocampal region. We measured the performance of active avoidance (AA) tasks, various enzyme activities and total glutathione content (TGC) in the forebrain cortex (FbC), striatum, basal forebrain (BFb), hippocampus, brain stem and cerebellum. AlCl3 markedly reduced AA performance and activities of cytochrome c oxidase (COX) and acetylcholinesterase (AChE) in all regions. It decreased TGC in the FbC, striatum, BFb, hippocampus, brain stem and cerebellum, and increased superoxide dismutase activity in the FbC, cerebellum and BFb. GTLE pretreatment completely reversed the damaging effects of AlCl3 on AA and superoxide dismutase activity, markedly corrected COX and AChE activities, and moderately improved TGC. GTLE alone increased COX and AChE activities in almost all regions. GTLE reduces AlCl3 neurotoxicity probably via antioxidative effects and improves mitochondrial and cholinergic synaptic functions through the actions of (-)-epigallocatechin gallate and (-)-epicatechin, compounds most abundantly found in GTLE. Our results suggest that green tea might be beneficial in Alzheimer's disease.

The influence of comedication on tacrolimus blood concentration in patients subjected to kidney transplantation: a retrospective study.

Tacrolimus is an immunosuppressant used for the prevention of kidney allograft rejection. The effects of comedication on tacrolimus trough concentrations (TTC) in kidney transplant recipients, subjected to basic immunosuppressant regime consisting of tacrolimus, corticosteroids and mycophenolate mofetil were investigated. This retrospective case series study involved 208 of these patients, with the outpatient examination recorded in the database of patients, at the unit of monitoring, with a total of 5,011 such examinations. Binary logistic regression analysis has shown that calcium channel blockers, diuretics and proton pump inhibitors (PPIs) significantly affected TTC (p < 0.001). PPIs significantly increased the number of examinations in which the TTC were in the recommended therapeutic range (from 5 to 15 ng/ml), as well as over the therapeutic range (p < 0.0001). When calcium channel blockers were added to PPIs, even more pronounced effect was obtained in comparison to triple-drug therapy only (p < 0.0001). In case a diuretic was given with a PPI, a significantly increased number of examinations with subtherapeutic TTC was observed when compared with PPI only (p = 0.0203). The combination of calcium channel blockers, diuretics and PPIs resulted in the number of examinations with TTC in the recommended therapeutic range not being different from the number of examinations with TTC in the triple-drug therapy only (p = 0.3829). ß-adrenergic antagonists can be administered without fear of affecting the tacrolimus optimal therapeutic concentrations. This was confirmed with all combinations of the examined drugs used in patients subjected to kidney transplantation concomitantly with ß blockers.

Beneficial effect of agmatine in the acute phase of experimental autoimmune encephalomyelitis in iNOS-/- knockout mice.

The aim of the study was to investigate the hypothesis that agmatine (AGM) provides protection against oxidative stress in experimental autoimmune encephalomyelitis (EAE). Wild-type (WT) and knockout (KO) CBA/H iNOS-/- 3 months old (15 ± 5 g) mice, were used for EAE induction by myelin basic protein (MBP), dissolved in Complete Freund's Adjuvant (CFA). The animals were divided into control, EAE, CFA, EAE+AGM and AGM groups. After the development of full clinical remission, animals were decapitated and oxidative stress parameters were determined in whole encephalitic mass (WEM) and cerebellum homogenates. The EAE clinical expression manifested to greater extent in WT than KO mice, was significantly decreased during AGM treatment. We demonstrated significant elevations of superoxide dismutase activity in WT and KO EAE animals, in WEM and cerebellum tissues, which were decreased during AGM treatment in both groups. Superoxide anion content was increased in WEM of both study groups, with a decrease during AGM treatment. The observed changes were more pronounced in WT than in KO animals. Also, the increased expressions of transferrin receptor and glial fibrillary acidic protein observed in WT and KO EAE mice were significantly decreased during AGM treatment. The results suggest potentially beneficial AGM effects in EAE, which might be used for a modified antioxidative approach in MS therapy.

Efficacy of amifostine in protection against doxorubicin-induced acute cardiotoxic effects in rats.

BACKGROUND/AIM: Amifostine (AMI) is a broad-spectrum cytoprotector which protects against variety of radio- and chemotherapy-related toxicities without decreasing their antitumor action. The aim of the study was to investigate the potential protective effects of AMI against acute cardiotoxic effects of doxorubicin (DOX) in male Wistar rats. METHODS: AMI (300 mg/kg ip) was given 30 min before DOX (6 mg/kg and 10mg/kg b.w., iv). The evaluation of DOX-induced cardiotoxic effects, as well as cardioprotective efficacy of AMI was performed 48 h after their administration by determining serum activities of enzymes known to be markers of cardiac damage (creatine kinase - CK, aspartate aminotransferase - AST, lactate dehydrogenase - LDH, and its isoenzyme alpha-hydroxybutirate dehydrogenase - alpha - HBDH), as well as the histopathological and ultrastructural analysis of the heart tissue. RESULTS: AMI successfully prevented a significant increase in serum activity of CK, AST, LDH and alpha-HBDH in animals treated with DOX in the dose of 6 mg/kg (121.14 +/- 18.37 vs 167.70 +/- 44.24; 771.42 +/- 161.99 vs 1057.00 +/- 300.00; 3230.00 +/- 1031.73 vs 4243.10 +/- 904.06; 202.57 +/- 42.46 vs 294.90 +/- 80.20 UI/l, respectively), and ameliorated DOX-induced structural damage of the rat myocardium. Pretreatment with AMI in rats given 10 mg/kg DOX reduced the cardiac damage score (CDS) from 2.62 +/- 0.51 to 1.62 +/- 0.51, i.e. to the CDS value obtained with the lower dose of DOX (6 mg/kg). The ultrastructural analysis of the rat myocardium showed that AMI successfully protected the sarcolemma of cardiomyocytes and reduced mitochondria damage induced by DOX given in the dose of 6 mg/kg. Besides, capillaries were less morphologically changed and apoptosis of endothelial cells was extremely rare in AMI-protected animals. AMI itself did not cause any prominent changes in the examined parameters in comparison with the control rats. CONCLUSION: AMI provided a significant protection against DOX-induced acute cardiotoxic effects in rats. This finding implies its potential to be a successful cardioprotector in patients treated with DOX due to malignant diseases.

Influence of NG-nitro-L-arginine methyl ester on clinical and biochemical effects of methylene blue in pentylenetetrazole-evoked convulsions.

BACKGROUND/AIM: Despite years of research in a number of experimental models the question whether nitric oxide (NO) and methylene blue (MB) have pro- or anticonvulsant effects remains to be fully resolved. Methods. In adult Wistar rats the influence of a nonselective inhibitor of nitric oxide synthase NG-nitro-L-arginine methyl ester (L-NAME, 10 microg) on clinical and biochemical effects of MB (10 microg) given before the intraperitoneally administered chemical convulsant pentylenetetrazole (PTZ, 80 mg/kg) was examined. MB and L-NAME were applied intracerebroventricularly. PTZ application was followed by a 4-minute observation time, after which rats were sacrificed and elements of oxido-reductive balance were measured in a crude mitochondrial fraction of forebrain cortex, hippocampus and striatum. RESULTS: Convulsive responses (forelimb dystonia--FLD, generalised clonic- and clonic-tonic convulsions--GCC and GCTC respectively) were observed in all rats received PTZ, together with significantly decreased lipid peroxidation in the forebrain cortex and striatum and increased superoxide dismutase activity in the hippocampus, in comparison to controls (saline treated). It was registered anticonvulsant effects of L-NAME pretreatment. However, these effects were insignificant. In the hippocampus of these animals there was decreased lipid peroxidation (p < 0.01, p < 0.05 vs saline-treated and PTZ-treated rats, respectively) and reverted PTZ-induced increase of superoxide dismutase activity. But MB individually pretreatment significantly decreased the incidence of CTCs and GCCs (FLD: p = 0.0513), prolonged the convulsive latent time for FLD, GCTCs and GCCs, in all the examined brain regions increased lipid peroxidation and decreased the level of superoxide anion. Administration of L-NAME 10 minutes before MB reverted all MB-evoked clinical and biochemical effects. CONCLUSION: Methylene blue applied individually before PTZ has strong anticonvulsant effects that were eliminated by L-NAME pretreatment. These effects and changed biochemical parameters in the brains of animals treated by L-NAME before MB in comparison to MB-treated group suggest involvement of NO in MB's effects in the animal model of PTZ-evoked convulsions.

N-nitro-L-arginine methyl ester influence on aluminium toxicity in the brain.

We investigated the influence of a non-specific nitric oxide synthase (NOS) inhibitor, N-nitro-L-arginine methyl ester (L-NAME), on brain nitrite concentration and acetylcholine esterase activity in AlCl3-treated Wistar rats. Animals were killed 10 min, three hours, three days and 30 days after the treatment and hippocampus and basal forebrain were removed. The biochemical changes observed in neuronal tissues show the involvement of NO in the AlCl3 toxicity and cholinergic neurotransmission, and that L-NAME may have potential neuroprotective effects. Active avoidance learning was significantly impaired after AlCl3 application, while pretreatment with L-NAME prevented the behavioural deficits caused by AlCl3. We also applied immunohistochemical techniques to identify changes induced by AlCl3, L-NAME+AlCl3, as well as L-NAME injections after survival periods of three days and 30 days. Immunoreactivity of astrocytes and phagocytic microglia based on glial fibrillary acidic protein (GFAP) and a useful marker for rat macrophages (ED1), respectively, revealed a greater inflammatory response in AlCl3-injected animals compared to controls.

[Antidotal effect of combinations obidoxime/HI-6 and memantine in mice poisoned with soman, dichlorvos or heptenophos].

INTRODUCTION/AIM: In acute organophosphate poisoning the issue of special concern is the appearance of muscle fasciculations and convulsions that cannot be adequately antagonised by the use of atropine and oxime therapy. The aim of this study was to examine atidotal effect of obidoxime or HI-6 combinations with memantine in mice poisoned with soman, dichlorvos or heptenophos. METHODS: Male Albino mice were pretreated intravenously (iv) with increasing doses of oximes and/or memantine (10 mg/kg) at various times before poisoning with 1.3 LD-50 of soman, dichlorvos or heptenophos, in order to determine the median effective dose and the efficacy half-time. In a separate experiment, cerebral extravasation of Evans blue dye (40 mg/kg iv) was examined after application of memantine (10 mg/kg iv), midazolam (2.5 mg/kg intraperitonealy--ip) and ketamine (20 mg/kg ip) 5 minutes before soman (1 LD-50 subcutaneously--sc). RESULTS: Coadministration of memantine induced a significant decrease in median effective dose in null time of both HI-6 (7.96 vs 1.79 gmoL/kg in soman poisoning) and obidoxime (16.80 vs 2.75 micromoL/kg in dichlorvos poisoning; 21.56 vs 6.63 micromoL/kg in heptenophos poisoning). Memantine and midazolam succeded to counteract the soman-induced proconvulsive activity. CONCLUSION: Memantine potentiated the antidotal effect of HI-6 against a lethal dose of soman, as well as the ability of obidoxime to antagonize the toxic effects of dichlorvos and heptenophos probably partly due to its anticonvulsive properties.

Nitric oxide synthase inhibitors protect cholinergic neurons against AlCl3 excitotoxicity in the rat brain.

The present experiment was carried out to determine the effectiveness of nitric oxide synthase inhibitors: 7-nitroindazole and aminoguanidine in modulating the toxicity of aluminium chloride on acetylcholine esterase activity, as well as behavioural and morphological changes of Wistar rats. For biochemical analysis the animals were killed 10 min, 3 h, 3 days and 30 days after the treatment and forebrain cortex, striatum, basal forebrain and hippocampus were removed. The biochemical changes observed in neuronal tissues show that nitric oxide synthase inhibitors exert as protective action in aluminium chloride-treated animals. In the present study, active avoidance learning was significantly impaired after aluminium chloride injection, while pretreatment with nitric oxide synthase inhibitors prevented the behavioural deficits caused between 26th and 30th day after intrahippocampal application of neurotoxin. Our data suggest that aluminium may cause learning and memory deficits, while the treatment with specific nitric oxide synthase inhibitors may prevent learning and memory deficits caused by aluminium chloride. We have also applied immunohistochemical techniques to identify neuronal- and inducible-nitric oxide synthase expression 30 days after aluminium chloride and nitric oxide synthase inhibitors injections. Our data suggest that 7-nitroindazole and aminoguanidine can be effective in the protection of toxicity induced by aluminium chloride.

Systemic and intraperitoneal proinflammatory cytokine profiles in patients on continuous ambulatory peritoneal dialysis.

Our cross-sectional study included 44 patients (27 men, 17 women; mean age: 57.12 +/- 16.66 years; mean dialysis treatment period: 3.59 +/- 2.67 years) on continuous ambulatory peritoneal dialysis (CAPD). Of the 44 patients, 21 were using standard solutions (Stay*Safe, ANDY-disc: Fresenius Medical Care, Bad Homburg, Germany), and 23 were using biocompatible solutions (Gambrosol Trio: Gambro Lundia AB, Lund, Sweden; Stay*Safe Balance: Fresenius Medical Care). In all CAPD patients dialyzed longer than 6 months, we analyzed levels of interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha), and interleukin 6 (IL-6) in serum and dialysis effluent when patients were free of acute infection-related (CAPD peritonitis, exit-site infection, other acute infections) complications. In a control group of 20 patients with chronic renal failure [CRF (stages IV and V)], we also determined serum levels of the same cytokines. Levels of the inflammatory cytokines were measured using specific commercial ELISA kits (BioSource, Camarillo, CA, U.S.A.). Statistical analysis of the results was performed using commercial statistics software for the PC (Statistica for Windows, rev. 4.5: StatSoft, Tulsa, OK, U.S.A.). Serum levels of LL-1beta and IL-6 were not statistically significantly different between the patients on CAPD, regardless of the type of dialysis the used, and between the patients and the control group with CRF. Serum levels of TNFalpha, unlike those for IL-1beta and IL-6, were statistically significantly higher in patients on CAPD than in the control group with CRF (13.20 +/- 3.23 pg/mL vs. 5.59 +/- 4.54 pg/mL, p < 0.001, Mann-Whitney test). Serum and effluent IL-1beta levels in patients on CAPD for less than 1 year and more than 1 year did not significantly differ, but effluent IL-6 levels were significantly higher than serum IL-6 levels in both groups of patients, and effluent IL-6 levels were significantly higher in CAPD patients dialyzed for more than 1 year than in patients dialyzed for less than 1 year. Serum and intraperitoneal (IP) levels of the examined cytokines did not significantly differ in patients on standard and biocompatible solutions, but a trend toward lower IP levels of IL-6 was seen in patients on biocompatible solutions. Residual renal function and number of episodes of CAPD peritonitis had no important effect on serum and IP levels of the examined cytokines. Elevated serum levels of TNFalpha and significant local IL-6 production in our CAPD patients indirectly confirmed the importance of peritoneal dialysis (PD) in amplifying the chronic inflammation that substantially depends on duration of dialysis treatment.

[Arthroscopic findings after shoulder dislocation].

BACKGROUND/AIM: Recurrent instability of the shoulder joint is frequently difficult to differentiate from diseased or injured rotator cuff or tendon of the forearm flexor (m. biceps brachii). Shoulder joint arthroscopy has been only recently introduced into instable shoulder joint lesion examination. The aim of this study was to present and analyse an arthroscopic finding on instable shoulder joint in order to determine causes and mechanisms of instability, as well as principles of surgical treatment. METHODS: Arthroscopy of the shoulder joint was performed in 158 patients with at least one documented shoulder joint dislocation. These patients were divided into two groups. The group I included the patients with one to three dislocations, while the group II those with more than three dislocations. Preoperative diagnosis was based on anamnestic data and clinical examination using specific tests, and on the diagnosis of shoulder joint using radiography or computed tomography. RESULTS: Out of the total number of the patients 138 (87.34%) had injury of the anterior patellar brim, 119 (75.32%) had failure of the anterior capsule, 126 (79.75%) had compressive cartilage injury of the posterior part of the head of the upper arm bone (Hill-Sachs lesion), 102 (64.56%) had insufficiency of glenohumeral tendon, 11 (6.96) had complete cut of the rotator cuff, 23 (14.56%) had injury of the posterior patellar brim, 12 (7.59%) had injury of the upper anterior-posterior patellar brim (SLAP). CONCLUSION: According to the obtained results it could be concluded that there is no a unique injury that leads to shoulder joint instability. It is necessary to point out to the significance of anamnesis and clinical examination in making diagnosis. Arthroscopic diagnostics is indicated in clinically unreliable findings as an additional method for determining operative treatment.